When I worked at Transit App, I built a backend pre-processing pipeline to compress transit and osm data in python [1] and also another pipeline to process transit map data in python [2]. Since the Ops people complained about how long it took to compress the transit feeds (I think London took 10h each time something changed), I migrated everything to Pypy. Back then that was a bit annoying cuz it meant I had to remove numpy as a requirement, but other than that there were few issues. Also it meant we were stuck on 2.7 for quite a while, so long that I hadnt prepared a possible migration to 3.x. The migration happened after I left. Afaik they still use pypy.

Python is fun to work with (except classes…), but its just sooo slow. Pypy can be a life saver.

[1] https://blog.transitapp.com/how-we-shrank-our-trip-planner-t... [2] https://blog.transitapp.com/how-we-built-the-worlds-pretties...